错误＆＃34;必须实现继承的抽象方法＆＃34;

Question

错误已解决且应用运行。问题是我如何在应用程序中的amound字段中添加一个监听器？由于应用程序现在它只是总结为ex＆＃34; sek 1＆＃34; +＆＃34; usd 6.69＆＃34; =＆＃34; 7.69＆＃34;。 任何好的想法如何使这项工作？

这是我的代码：

package com.example.currencyconverter;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.TextView;


public class MainActivity extends Activity {
 private String [] currency_name;
 private ArrayAdapter<String> adapter;
 private Spinner spin1, spin2;

 @Override
 public void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
 setUpTheSpinners();
 }
 @Override
    public boolean onCreateOptionsMenu(Menu menu) {

        return true;
    }


 private void setUpTheSpinners() {
 currency_name = getResources().getStringArray(R.array.currency_name);
 adapter= new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, currency_name);
 adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
 OnItemSelectedListener listener = new CurrencySelectedListener();
 spin1 = (Spinner)findViewById(R.id.spinner1);
 spin1.setAdapter(adapter);
 spin1.setOnItemSelectedListener(listener);
 spin2 = (Spinner)findViewById(R.id.spinner2);
 spin2.setAdapter(adapter);
 spin2.setOnItemSelectedListener(listener);
 }

 private void calculateSum() {
 String [] rates = getResources().getStringArray(R.array.currency_rate);
 int index1 = spin1.getSelectedItemPosition();
 int index2 = spin2.getSelectedItemPosition();

 double rate1 = Double.parseDouble( rates[index1] );
 double rate2 = Double.parseDouble( rates[index2] );

 double totalRate = rate1 + rate2;
 TextView totalRateText = (TextView)findViewById(R.id.textView4);
 totalRateText.setText("" + totalRate);
 }

 private class CurrencySelectedListener implements OnItemSelectedListener {

 public void onItemSelected(AdapterView<?> parent, View view, int pos, long id) {
 calculateSum();
 }

 public void onNothingSelected(AdapterView<?> parent) {
 }
 }
}